This invention relates to electronic data cables in general and in particular to fiber optic cables which prevent high pressure gas from migrating the length of the cable.
In certain applications utilizing electronic data cables, it is very important that high pressure gases be prevented from migrating the length of the data cable. One such application is in cables used to monitor down hole nuclear tests. Migration of the high pressure gases the length of the cable would contaminate sensitive equipment and personnel. For example, Department of Energy-Nevada-Fiber Optic (DOE-NV-FO) specifications require zero leakage and zero evidence of any displacement, protuberance, rupture, or change throughout each test specimen, after bending and temperature cycling preconditioning, during the 862KPA (125 Ps1g) minimum gas block test period specified in the purchase order or detail specification.
In the past, no cables designed as gas blocked cables were reliable. The industry has accepted as a compromise gas "blockable" cables in which metal bands or other means were installed around the cable to prevent migration of high pressure gases along the length of the cable.